Automatic message exchange system



March 19 1940- E. E, KLr-:lNscHMm-r 2,193,967

,AUTOMATIC MESSAGE EXCHANGE SYSTEM Original Filed Jan. 5, 1933 9Sheets-Sheet 1 LQ Ebb March 19;P 1940- E.; |.En-|scl|Mu:rl 2,193,967

AUIOKATIC MESSAGE EXCHANGE SYSTEM original Filed Jan. 5. 195s 9sheets-sheet 2 .32/ 303 4 soa `302 AT1-ORN Y March 1,9, 1940 E. E.KLl-:lNscH'MlD-r j 2,193,967'

AUTouA'rIc MESSAGE EXCHANGE SYSTEM l A original Filed Jan. 5.1933 9sheets-511991 4 INVENTOR 5 ATTORNEY was;

Mardi 19 1940- E. E. KLElNscHMlDT AUTOMATIC MESSAGE EXCHANGE SYSTEMOriginal Filed Jan. 5, 1933 9 Sheets-Sheet 5 E. E. KLEINSCHMIDTAUTOMATIC: MESSAGE EXCHANGE SYSTEM March 19, 1940.

original Filed'n. s, 1933 9 sheets-sheet s Mardi 19 1940 E. E.KLElNscHMlD-r 2,193,967

AUTOMATIC MESSAGE EXCHANGE SYSTEM Original Filed Jan. 5, 1933 y 9Sheets-Sheet '7 FVG. Q

March 19, 1940- E. E. KLElNscHMlDT I AUTOKATIC MESSAGE EXCHANGE .SYSTEM9 sheets-sheet original File Jan. 5, 1933 ATTORN Y Mardi 194 l940- E. E.KLl-:lNscl-IMIDT AUTOMATIC MESSAGE EXCHANGE SYSTEM Original Filed Jm. 5,1933 9 Sheets-Sheet 9 426 4g@l BMZ 6?/ ATToR Y Patented Mar. 19, 19402,193,967

UNITED STATES PATENT y OFFICE AUTOMATIC MESSAGE EXCHANGE SYSTEM EdwardE. meinschmiat, nig-mami Park, 111., as-

sgnor to. Tcletype Corporation, Chicago, Ill., a corporation of DelawareApplication January 5, 1933, Serial No. 651,737

Renewed March 30, 1938 120 Claims. (Cl. 178-3) The present inventionpertains tomethods of transmitting, receiving, recording, and retrans;and lmeans for handling telegraph trame in a, mitting devices and withautomatic line-switching telegraph system comprising a plurality ofinterdevices such that the record of a message as reconnected centraloiiices and a plurality' of subceived at its originating central ofcewill control 5 stations connected thereto and more speciiicallylautomatic selective devices to set up a communi- 5 to an automatictelegraphic communication syscation circuit from that central oice tothe destitem. y nation of the message.

The invention pertains also specifically to auto- Another object ist0.rec01d a message in a form matic receiving, routing and delivering oftelef suitable for controlling its retransmission with v l graphmessages, to automatic switching of telethe address portion thereofutilized to control 10 graph lines, to automatic selection of telegraphautcmatic switches t0 ccnnccl' a rcl'fransmittel' y lines, to automatictransmission, registration and over Selected lines to the indicateddestination, retransmission of telegraph messages over telethenretransmitting the message tothe indicated graph lines which have beenlselected automatidestination, and then automatically returning a lcally, to transmission of an answerback message Checking message t0 thepcint 0f Origin t0 indi- 15 indicating delivery of a principal message,and to cate the delivery 0f the message.

recording automatically information from which A feature 0f theinvention is the DIOVisiOn 0f tra'ic'charges may be computed. anautomatically operative telegraphic checking According to presenttelegraph practice in system to increase the reliability of the transycities, a main or central te1egraph oince is supplemission of theaddress portion 0f the message. 2o

mented by many substation onices which are een- A further feature is toprovide recording denected to the central oiiice by local telegraphlines Vices t0 Produce I'ec01ds 0f transmitted messages equipped withautomatic printing' telegraph ma-I from which charges for the servicerendered may chines. These machines operate to transmit' becomputedmessages to the central oce for retransmission A further featureis t0 providemeans for autO- 25 therefrom over intercity lines. Such amessage matically compiling and transmitting a return is received in thecentral olilce by printing upon checking message When each Principalmessage is a tape which then is assigned to an operator in received atits destination station, the return charge of a line extending to itsdestination, and Checking message being compiled autcmatically 30. thenthe message is retransmitted either by operto comprise the signature ofthe principal mesation of a keyboard transmitter or by perforating SageaS an address for the return checking mesa tape which then is passedthrough an automatic Sage and to comprise the address 0f the Principaltransmitter. The printed tape is physicany message as a signature forthe return message. transported from its location of reception in the Afurther feature is t0 route t0 a Supervisory central oiilce to thelocation of the retransmitting Operator all'messages having imperfectaddresses 35 operator, and` personal attention is required for v 0raddresses nOt Served bythe Provided autclnatic the message in threeseparate instances; namely, Switching facilitiesy by a receivingoperator, by a physical carrying The above and other objects andfeatures of the messenger or mechanism, and by a retransmittinginvention are accomplished by the arrangement Jperator. If a message isdestined for a station 0f a telegraph communication system involving a`40 located at a distant central oilice, the present plurality of centraloflices to which are connected practice is for an address operator atthe distant a plurality -of branch stations. and which are centralstation to receive the message on a printed equipped With automaticSwitching mechanism tape. The printed tape is then physicallytranspermitting the automatic establishment of a com-- ported to asending operatorwho transmits the municating circuit between a branchstation and 45 message to the station of nal destination. its centralofiice, and between that central oice The principal object of thepresent invention is and other branch stations of a different centralthe provision of a telegraph system arranged to oiiice. 'Iheestablishment of the intercommunifacilitate and expedite thetransmission of meseating circuit between the branch station and itssages by the automatic establishment of comcentral oilice is effectedthrough the operation'of 50 munication circuits as determined by the adacalling key at the branch station which placesv dresses 0n the' Originalmessages. that station in communication with printing tele- A furtherobject of the invention is to provide a grapn apparatus, such as areperforator located lsystem of telegraph central ofces and telegraphlat its central cnice. Following this connection,

substations equipped with automatic telegraph the calling subscribertransmits the coded address of the called subscriber in duplicate, thebody of the message, and the coded signature of the calling subscriberalso in duplicate. Each of these portions is reproduced at the centralstation in a tape in the form of groups of perforations.

This perforated tape constitutes a record form or control form foroperating automatic switches to select circuits and for transmitting themessage. The arrangement of the address of the calling subscriber induplicate code formation functions with a specially designed transmitterfor determining the accuracy of the perforation of the address, so thatif an error appears therein a mechanism will be operated automaticallyfor signalling an attending operator, who will receive the entiremessage on a receiving printer and make the necessary changes in theperforated record to permit the establishment of the originally intendedcommunicating circuit.

Two sets of perforating apparatus are located at the central ofdce, onefor urgent and the other for deferred messages which alternativelyreceive the message from the branch or calling station, and whichcooperate with a specially designed tape transmitter for establishingthe communicating circuit to the called station automatically inaccordance with the perforated address in the tape. .'I'he'selection ofthese perforators forgoperation is determined by the first communicationsignal of the first letter of the code identified with .the calledsubscriber.

- 'I'he establishment of the communicating cirarranged responsive to theselection of 'a busy line to indicate that condition to the operator atthe central omce of the originating subscriber.

If the line of the called subscriber is free. and provided an idle trunkbetween the central oiflces has been seized, the printing telegraphapparatus of the called station is connected in operative communicationwith the transmitting apparatus at the sending cnice of the originatingsubscriber, and the transmission of the entire message including thecode address of the calling subscriber and that of the sender induplicate is effected.

Upon the completion of the transmission of themessage and thetransmission of special designating groups of code impulses, amechanismv responds to perforate a tape with the coded address of theoriginal sender and that of the called subscriber, which is insertedautomatically by the operation of apparatus prearranged with this? codedimpulses representative of the coded adv dress of the calling and calledsubscribers will be transmitted to the calling subscriber overconnections established automatically which willfbe received by thecalling subscriber andl servegas an indication that the message has beentransmitted to and received by the called subscriber.

To provide for the -automatic recording of mes-f sages from whichservice charges may be quickly perforators operative are shown in Fig.5. I

and readily determined, a counting mechanism including printing elementsis provided lat each subscribers station for automatically recording theaddress and the number of words included in each message. From such a.record the charge for services rendered in the transmission'of themessage may be computed.

A better understanding of the invention may be had from the followingdescription, taken in conjunction with the accompanying drawings,wherein,

Fig. 1 shows a diagram of the arrangement of circuits and apparatus ofthe system of this invention;

Fig. 2 shows a tape perforated with an address and. part of a messagefor urgent transmission service; l l

Fig. 3 shows a tape, perforated with an address and part of a messagefor deferred transmission service;

Fig. 4 shows circuits in detail for the equipment of a subscriber lineadapted to call 'the central oilice and adapted to be called from thecentral oilice;-

Fig. 5 shows circuits in detail for the two' alternative perforators,including message indicators;

Fig. 6 shows circuits in detail of address and message transmitters, atape return device and circuits to a correction desk;

Fig. 7 shows circuits of iirst and second selectors and indicatescircuits for trunking to other central offices in distant districts;

Fig. 8 shows circuits of third and fourth selectors and indicatescircuits for trunking to omces lin the same district;

Fig, 9 shows circuits of an answerback system:

Fig. 10 shows circuits of a final selector;

Fig. 11 shows an arrangementof other ngures to produce a completecircuit diagram in which Fig. 4 appears at the left of Fig. 5 to showthe calling substation and appears again dotted at right of Fig. 10 toshow the called substation:

Fig. 12 shows circuits for an extended trunk to another cnice in thesame district;

Fig. 13 shows plan view of parts of an accounting device;

Fig. 14 is an elevation and view of parts or the accounting device withdetail of electrical lcircuits and,

Fig. 15 shows mechanical -detail of a message indicating device.

GlNmaAL SYs'rmr ron nu: Drs'ramu'non or Mlssson Fig. 1 is a diagramshowing an arrangement of several types of switches used in transmittinga message from one substation to another substation within one centraloiiice and indicating trunk circuits for transmission of similarmessages addressed to substations in other central otlices in the samedistrict as well as in other districts. f i

In Fig. 1, substations I0, Il, and I2 each has a receiving lprinter Iland a transmitter I4' shown diagrammatically, the circuits of which areshown in detail in Fig.' 4. Each substation is connected by a line wireI I, I8. and II to an automatic trunk-under switch Il, also shown inFig. 4. Trunks I l are communication wires which may be selected by theswitch s and' each trunk I1 is connected by wires 20 and 2| to twoperforators, 22 and 23. The details of these perforators and theselective circuits and f devices for rendering one orthe other of theEachperforator is associated with an address l transmitter 24 forretransmitting the address Il portion of the message and a messagetransmitter 25 for retransmitting the entire message, comprisingaddress, body, and signature portions of the message. Each assembly ofperforator and two transmitters, as 22, 24, and 25, has

permanently associated with it an automatic trunk selector 26 or 21,which are shown in detail in Figs. 6 and '1 respectively.

Each of the selectors 26 responds to signals from the addresstransmitter 24 to set up a selectivecondition by which, first a group oftrunks leading to a common destination is selected, then an idle trunkin that group is selected and seized, and the two transmitters 24 and 25then are associated with the seized trunk .and with its remote selectorin a manner permitting the operation of the seized trunk and remoteselector under control of the transmitter 24. Thus the perforator 22 andits transmitter 24 are ladapted to operate their associated rst selector26 to seize a` second selector 34 or 36, to operate the second selectorto seize a third selector 46 or 42, to operate the seized third selectorto seize a fourth selector 44, to operate the seized fourth selector toseize a fifth or nal selector 50 or 52, and to operate the seized finalselector to seize one of the three lines I5, I8, and I9 leading to thethree substations II), II, and I2, respectively.

The nerforators and selectors here mentioned, all

of which have been given labels of even numbers, are assigned to theservice of-urgent messages. There is provided also separate equipment,perforator 23, Fig. 1, and associated transmitters, for service ofdeferred messages. Transmitter 24 lof the set 23, 24, and 25 is adaptedto operate its associated rst selector 21 to seize a second selector 35or 31 to operate the seized second selector to seize a third selector 4Ior 43, to operate the seized third selector to seize a fourth selector45, to operate the sei'zed fourth selector to seize a fth or nalselector 5I or 53 and to operate the seized iinal selector to seize oneof the three linesv I5, I8, or I9 leading to the three substations IIJ,II, and I2, respectively. The perforators and selectors here mentionedas assigned to the services of deferred messages have been given labelsof odd numbers. \The first, second, third, fourth, and nal selectors arealike. Each final selector contains an answerback device 54.

To give preference tourgent messages over dei'erred messages in thesystem herein described, it is proposed that central oice attendantswill assign sufcient trunk circuits both within the central olces andthose connecting central offices to urgent message transmission alwaysto carry the trafllc load without delay. When the urgent trafc is heavy,the excess of deferred messages will be held in the form of perforatedtape at the transmitters until decreasing traffic in urgent messageswill' permit the manual switching of trunk circuits to carry deferredmessages. Keys v |55, Fig. 1, are for the purpose here described.

y eating apparatus 62 and 64 and is connected with receiving apparatus82 in another central oilice in a distant district. Details thereof areshown in Fig. '1. Trunk 6I is similarly equipped. Trunk 58 extendsthrough home communicating apparatus 56 to receiving apparatus I 56 in anearby central oilice in the same district, Fig. 12, and trunk 59 fordeferred messages is similarly equipped.

GENERAL OPERATION Assume that an operator at substation I0, whosetelegraphic address is BOTIK, desires to send an urgent message tostation I2, whose telegraphic address is BOTIF for urgent messages. Theoperator depresses a calling key 30| at substation I0, switch I6responds in a well known manner and selects trunk I1 and its twoperforators 22and 23. A starting signal is shown at station I0 and theoperator proceeds to transmit the message. The two perforators 22 and 23register the first signal of the letter B, and as the letter B isindicative of an urgent message and not a deferred message, selectivedevices associated with the perforators 22 and 23 operate to render thedeferred perforator 23 inoperativ'e during the remainder of the message.The perforator 22 records address, body, and

signature upon its tape. The operator then sends 2 a message-end-signalof blank code and central oce apparatus acts to release calling line I5.

Beginning under control of the message-end signal code in the perforator22, address transmitter 24 acts over trunk 66 Fig. l, to register letterB upon the selector 26 and to connect transmitter 24 to trunk 68 of Bgroup of trunks for urgent messages. The address transmitter 24 thenacts over trunk 66 through selector 26 and over trunk 68 to registerletter O upon selector 34 and to connect the trunk 68 ro trunk I0 of BOgroup of trunks. The address transmitter 24 then acts over trunks 66,68, and 'I0 to register letter T upon selector 40 and to connect thetrunk 10 to trunk 80 of BOT group of trunks. The address transmitter 24then acts over trunks 66, 68, 10, and to register letter I upon selector44 to connect the trunk 8|!v to trunk 12 of BOTI group of trunks. Theaddress transmitter 24 then acts over trunks 66, 68, 10, 80, and 'I2'toregister letter F upon nal selector 5|) to connect the messagetransmitter 25 of perforator 22 to line wire I 9 and.to substation I2 asidentied by the address code BOTIF.` The message transmitter 25 receivesa signal that substation I2 is incondition to receive amessage andimmediately the message transmitter 25 sends the.full

` message comprising address, body, and signature vice 54 shown indetail in Fig. 9, which is responsive to a signal code which precedesthe signature. When this device is actuated, it operates to record thesignature ofthe message, then to act as a sender to send to a perforator14 a message comprising the recorded signature BOTIK as an address andthe directory number BOTIF of the connected line I9 as a signature. Thetransmitters 13 and 15 then control selectors 16, 34, 40, 44, 5l) orsimilar selectors to select line wire I 5 to substation I0 and achecking message BOTIK BO'I'IK BO'IIF is printed at substation I0 toindicate delivery of the principal message at 'substation I2.

A record' of the message for accounting or service charging purposes ismade by a'substation device not shown in Fig. 1 but shown in detail inFigs. 13 and 14.

THE SUBsTATioN AND I'rs FINDER SwrrcH At the substation I0, Fig. 4, aretelegraph sending contacts I4 and receiver magnet I3, showndiagrammatically. Symbol I4 may represent a transmitter of anykindeither keyboard contacts or automatic contacts controlled by aperforated tape. A motor 300 is provided for driving printer andtransmitter. There is provided also a calling key 30| having vecontacts. The key 30| is adapted to beoperated manually and to be heldin operated position by a latch 302 which is also an armature of magnet303. The latch 302 has an electrical contact 304 which engages to closea circuit when attracted by magnet 303. The magnet 303 is polarized andoperates only when positive battery 36 I, Fig. 5, at the central officeis connected to line I5. Motor 300 has a pair of contacts 305 which areclosed only when the motor is operated at full speed and which areconnected to terminals of resistance 306.

A relay 301 has its winding connected in circuit C.2, from power mains3I0 through winding of relay 301, and through top contacts of key 30| tomains 3I0, and has its armature and contact connected in-parallel withthe keyboard contacts |4 An alternating current relay 3II, adapted torespond to current'of 135 cycles, has its Winding connected in circuitC.36 from line w'lre I5 through magnet I3, a condenser 3|2, and contactsof key 30| to ground 3I6. It has its upper armatureand contact connectedin a branch of circuit C.31 from line I5 through magnet I3, contacts I4,a resistance 305, winding 'and shunt 3I5 of a relay 3|3, upper armatureand contactof the relay 3|| and contacts of key 30| to ground, and

has its lower armature and contact connected in circuit C.3 from theright-hand wire of the power mains 3I0, through the lower armature andcon'- tact of relay 3| I, and through' the winding of a relay 3|4, amanual key 32|, an audible-signal device 3I1, and a lamp 320 to themains 3I0. The circuit C.3 also may be completed through armaturev 302of magnet 303 and its contact 304.

Relay 3I3 is of slow-to-release type, with its winding shunted by anon-inductive resistance 3|5, and has its windingv connected in circuitC.I, to the line wire and a contact of key 30|. Its upper armature andfront contact are connected to the fourth and illth contacts of the key30|. Its lower aipaature and front contact are connected to theright-hand wire of the power mains 3I0 and to one terminal of the motor300 whose ing of relay 3|4, then as C.8 to the mains'3l0.

The winding of magnet 303 is connected in circuit C.I, from the fourthcontact of key 30| to ground 303. The line wire I5 connectsthesubstation I to apparatus at the central oilce.

At the central omce, anA automatic switch I0 is individual to each lineI and is adapted `to connect the line I5 to'an idle trunk, such as trunkwire I1 and its companion test wire 322. Switch I5 has two brushes whichare driven by a ratchet 323 and a pawl 324 and an armature of a magnet325, which hasa return spring 326 and a pair of contacts 321..

relay 330 for controlling lswitch I5, a holding relay 33| forcontrolling a test relay 332 during transmission of a message, a testrelay 332 for detecting an idle trunk test wire when the switch I6 issearching, a relay 333 for detecting a busyby-test condition of line I5when line I5 has been selected by a nal selector.' to be described, arelay 334 for cutting off switch I6 and its apparatus from line I5 afterthe line' I5 has been seized by a nal selector, a shunt relay 335 forshunting a choke coil 336 which is needed in setting up communicationbut is not needed after communication has been established, and a slowrelay 355 for delaying restoration of line I5 to its battery 331 afterthe line has been released by relay 334 or by relay 33|. Battery 331 iscommon to a number of lines and is connected with its negative pole withthe lines and its positive pole to ground. A grounded ringing generator338 is connected in circuit C.36 through a condenser 339, normally opencontacts of relay-334 and closed contacts of relay 335 to line I5,thence to ground 3| 5 as described above.

The battery 331 is connected in circuit C.I, through winding of relay330, operating winding of relay 33|, and closed contacts of relays 365and 332 to the line wire I5,V thence through 'magnet I3, contacts I4,resistance 305, winding and shunt of relay 3I3, lowest two contacts ofkey 30| normally open, and winding of magnet "through lower or holdingwinding of relay 33|,

lower winding of relay 350, winding of test relay 332, a resistance 34|and lower contact and armature of relay 333 to ground 342. Relay 332 hasits top front contact connected to the communication brush of switchvI0. Its middle armature and front contact are connected tothe terminalsof resistance 34| to shunt that resistance. Its bottom armature and backcontact are connected in busy-test circuit C.35, to be described.

Associated with test wire 33 of each trimk I1 is a test-control relay350, Fig. 5. This relay has an upper or operating winding of 100 ohmscon- Inected in circuit-C.3, from negative pole of grounded battery 352,Fig. 5, winding of a slow- "to-operate relay 343, upper armature andback contact of relay 35|, back contact and armature of the relay 353and then through the upper winding of relay 350 to wire 322 and thenceas described above for circuit C.3 to ground 342, Fig. 4.

Relay 350 has a second winding of 1000 ohms,

' an external resistance 353 of 1000 ohms', and a dry copper oxide valve354 whose resistance is 50 ohms when traversed by current from thebattery 352, but is 5000 ohms when traversed by inducedV current fromthe lower winding ofthe relay 350 in response to the beginning ofcurrent in the upper winding of relay 35l. -The three elements contactof relay 350 so that the three series elements are shunted when therelay 350 is unenergized. 'I'he presence of the valve 354 reduces theinduced local current and increases the speed cuit .C.| to ground 3|Ii.ARelay 356 has its upper,-

winding terminals connected to upper armature and contact of relay 364,which has its lower armature and front contact connected in circuit4C.I5 to be described. Relay 356 has its lower or holding windingconnected in circuit C.1, from contact of relay 35| in circuit C.3,through winding of relay 364, winding of relay 356, through the frontcontact (normally open) and lower armature of relay 356 to ground 363.

A OPERATION OFTHE Flivmm SWITCH I In this description, the elapsing timeis divided into numbered intervals. The circuits also are numbered foreasy identification.

Time Q-All apparatus in condition of rest The circuit C.| of the line I5extends` from battery 331 through relays 330 and-33| at the central`oilce, and is open for direct current at condenser 3I2, at the armatureof relay 3I3, at the armature of relay 3| I, and at the fifth contact ofkey 30| at substation I0.

Time I-Initiating a message The latching calling key 30| atthefsubstation I0 in Fig. 4 is closed manually, is latched and closescircuits C.I and C.2, described above, the

circuit C.I being extended to ground 308` through `contacts of operatedkey 30| and winding of magnet 3.03.

Battery 331 produces in circuit C.I a current of m. a. which energizesrelays 330, 33|, and 3|3- but not printer magnet I3 because the currentis too weak, nor magnet 303 due to the connected negative terminal ofbattery 331. l

Relay 3I3 in operating closes and shunts the fourth and ilfth contactsof key 30 I, and connects the power mains 3I0 to the motor 300. Whenmotor 300 attains its operating speed contacts 305 are closed to shuntresistance 306..w Energy from the power mains 3| 0 produces in circuitC.2 a current to operate relay 301 whose contacts shunt'the keyboardcontacts I4 so that circuit C.I may be completed through-the contacts ofthe relay 301 in case the contacts I4 be open.

lTime 2'The period of search.

.relay 332 and 1000v ohms in resistance 34|, or

a total'of Z'ZOOohms, and the battery 352 of v110 volts produces anoperating current of 40 m. a.,

'suiiicient fo operate the relays 349, 350, 366, and' v 332 andtoholdthe operated relay 33| .The slowto-operate relay 349 will close itscontacts eilectively only when the motor 300 does not reach its maximumspeed within a predetermined time limit.

relay 332 connected through to an idle trunk test wire 322, relay 332and relay 350 will be energized by current in c'ircuit C.3, and theupper i' Should switch I6 lat this instant be holding test armature ofrelay 332 will interrupt circuit C.I to release relay 330 to opencircuit C.4 before magnet 325 has had time to step switch I6. Relays 332and 350 jointly will render the trunk wire 322 busy-by-tes't. Should twotesting relays 332 test the trunk wire 322 simultaneously, the resultantresistance of circuit C.3 would be 1450 ohms and the current would be'15 m. a. This is nearly double the normal current of relay 350 whichwould operate quickly and reduce the current through the two relays 332neither of which would operate, and the search would continue asdescribed below.

When a tested trunk wire 322 is busy-by-test, the resistance of circuitC.3 while -being tested is 100 ohms in relay 349, 1000 ohms inresistance 353, 50 ohms in valve 354, 1000 ohms in lower winding ofrelay 350, 100 ohms in upper winding of relay 350, 500 ohms in windingof relay l33|, 500 ohms in winding of relay 366, and 500 ohms in windingof relay 332 at the finder switch I6, which is using the busy trunk.Connected in shunt of the last 1500 ohms above listed are elements 33|,366, 332, and 34| at the switch I6 which is testing the busy trunk. Theresulting resistance of the total circuit C.3 is 3187 ohms and battery352 of 110 volts produces a current 'of 35 m. a. of which the testingrelay 332 receives but 13 m. a. which is suilcient to hold relay 332when operated, but relay 332 does not operate at this time to opencircuit C I and the relay 330 remains energized and holds circuit C 4closed.

Magnet 325, energized over circuit C.4, attracts its armature and by thearmature movement it" drives the brushes of switch I6 into engagementwith the next test contacts 355 and 365 thereof.

Should the second trunk be busy-by-test, relay 332 will notbe operated.Contacts 321 operated by the armature of magnet 325 will shunt thewindingof relay 330, thus deenergizing the relay 330 'whose contactsthenwill vopen and will deenergize the magnet 325 thus opening thecontacts 321.. Again relay 330 will become energized to repeat the cycleto-advance the brushes of the switch I6. When the-brushes 'of the switchI6 engage a wire 332 which is noty busy-by-test, test relay 332 willreceive 40 m. a. and will operate its armatures. Its lower armature andback contact will remove battery 345 from test wire 650 for incomingmessages and will render line I5 busyby-test.

In the condition of rest (Time 0) circuit C.5,

-from battery 36|, winding of. relay 360, lower armature and` backcontact of relay 35|, upper armature and back contact of relay 356, re-

` fsistance 362, to ground '363, has held repeating relay'360energized.-`

The top armature and front contact of operated'testrelay 332 now closetheprimary communication circuit 6, but temporarilyit is through magnet303 to ground 308.

Current through the upper winding of'relay 356 energizes the relay tooperate its armatures.

Its upper armature opens circuit C.5 and removes resistance 362 fromcircuit C.6 and its lower armature closes the holding circuit 0.1'thereby operating relay 364. Relay 364 shunts. the operating winding ofrelay 356 from circuit C.6 but relay 356 is maintained energized bycurrent in.

circuit C.1. Repeating relay 360 now is controlled by keyboard contactsI4 over circuit 0.6.

Magnet 303 unlatches key 30| which returns to normal position. Contactsin key 30| now shunt the winding of magnet 303, while other con- I amessage.

tacts thereof open circuit C.2 and deenergize relay 301.

Energization of magnet 303 has closed momentarily contact 304 toenergize relay 3|4 over circuit C.8. Relay 3I4 holds by 'current overcircuit C.9, lamp 320 glows and device 3I1 produces an audible signal.This is a signaling condition which notifies -the operator of thesubstation I that the line is connected for transmission of The samedevice will give an alarm when a message is received. The operator nowopens key 32| momentarily to discontinue the signals.

The system now is in condition for transmission by the operator atsubstation I0, using keyboard contacts I4. Without normal, speed inmotor 300, contacts 305 remain open; current in line I is below normaland printer magnet I3 will not respond. This constitutes an automaticsignal to the operator that transmission is not being effected.

Calling station I0 sends the first letter. Signals enter the centraloffice over circuit C 6 and operate repeating relay 360. Assume anurgent message whose first address letter is B as shown inFig. 2

THE Pnnnona'ron SYSTEM For each trunk I1, Fig. 5, there are provided twoperforators 22 and 23 of signal-controlled type in which perforation ofa tape is elected with holes arranged in code formation to representelectrical signals which have been received in code manner by theperforator system. `Such a device is described in United States Patent1,884,743, granted October 25, 1932, to E; E. Kleinschmidt. Such adevice comprises ve signal receiving magnets 31|, 312 .which operate vepunch control fingers 313 which control ve code punches 314 with whichis associated a xed punch for feeding holes. A power magnet 315 operatesthe punches after code combinations have been set upon magnets 31 I 312.

With each perforator 22 and 23 is provided a distributor 316, 311, atape follower switch 380. 38| and a message indicator 382, 383. Thesemechanisms are associated by circuits and relays, al1 organized to becontrolled primarily by the repeating relay 360.

Distributor 316 has a stop segment 381, ve code segments, a local switch384, and a brush arm 385 with its brushes adapted to engage the,E

segments and the local switch. Starting magnet 385 is normally energizedto hold its armature 390 attracted. Armature 390 has an electricalcontact 39| and has two mechanical stops for brush arm 385, a short-endstop for stopping the brush arm in normal position as shown andeffective when the armature is in its attracted position, and a long-endstop for stopping the brush arm in a pre-normal position. In each ofthese positions the brush arm engages the stop segment 381 and isdisengaged from local switch 384.

Start magnet 336 is connected in circuit C.I0 to stop segment 381 andarm 385 over wires 20 and 404 and contacts of relay 360 to battery 400,and also over a`common wire 392 through bottom contacts. of relay 393 toground 394. Start magnet 420 is connected similarly in circuit C.II,

' from battery 400, contacts of relay 360, wires 404 and 2|, arm 426,segment 42| and then wire 422 and contacts of relay 4|0 to ground 423.The ve x to corresponding magnets 31| and 312, then to wire 392 formagnets 312 or through winding of relay 40 to wire 392 for magnet 31|.Contact 39| and armature 390 of magnet 386 are connected in circuit C.I4through winding of relay 396 to battery 400 and over wire 40| to allarmatures of perforator magnets 31| and 312, thence through circuitsC.I2 and C.|5 to ground 394. Switch 384 is connected on one side throughwinding of test relay 402 to battery 400, and on the other side towinding of perforator power magnet 315 and through the bottom contactsof blanking relay 403 to common wire 392 and ground 394, thus formingcircuit C.I8.

Tape follower switch 380 when in normal position with tape 406 slack asshown, comprises normally closed contacts 401 connected in circuit C.39,to be described, and normally open contacts 409 connected to ground andto winding of relay 403 which is connected through middle contacts ofrelay 4I0 to battery 400, thus forming circuit C.40. The top armatureand contact of relay 403 are connected in circuit C.42 with battery 4|I, interrupter contacts 4|2 on magnet 4| 3 and the winding of magnet4|3, and the middle armature of this relay is connected to ground withits front contact thereof connected through resistance 4|4 to the trunktest wire 322, forming a branch path for busy-test circuit C.3. Vibratormagnet 4I3 has also a pair of contacts 4|5 operated by its armature andconnected through winding of power magnet 318 and through lowestarmature of relay 403 and its front contact to ground, and connectedalso through middle contacts of relay 4|0 to battery 400, thus formingcircuit C.43 when relay 403 is operated. These contacts are normallyopen and are closed when the magnet 4| 3 attracts its armature. Relay 4|0 has a lower locking winding which is connected from grounded wire 392and through, its own upper armature and Contact and' through the lowercontacts of relay 364 to battery 400, to form circuit C.I5, which whenformed holds the relay 4|0 energized through the transmission of thecomplete message. Magnet 4`I6a1so is included in circuit C.I5 in`parallel with the holding winding of relay 4|0.

As shown in Fig l5, a message indicator 332 includes a lixed shaft 430which carries two rotatable ratchets 43| each of which carries onecontact of the pair 435 and a collector ring 423. Contacts 435 andrings'429 are assembled upon ratchets 43| with insulating rings andbushed screws. Brushes 428 engage collectors 429 and are connected tobattery and to the winding of relay 432, Fig. 5, forming circuit 0.2

Perforator 23 is identical with perforator 22 except in the circuitconnections, which are reversed in two details. In perforator 22,current through rst magnet 31| (C.I2) energizes control relay 4|0 whilein perforator 23, current through first magnet 424 does not energizerelay 393 corresponding to relay 4|0. In perforator 22, current throughmagnets 312 (C.I6) does not energize .relay 4I0 while 'in perforator 23,current through magnets 425 will energize relay 398. Discrimination thusis effected.- between urgent messages and deferred messages. An urgentmessage (Fig. 2) willoperate relays 31| and 4|0 to remove ground 423from wire 422 and from all operating circuits of perforator 23, thusdisabling perforator 23 and permitting perforator 22 to record an urgentmessage, while a deferred message (Fig. 3) will not operate relays 31|and 4|8 but willl operate a relay 425 and relay A393 to re7 'I5 moveground 394 from wire 392 and from all operating circuits of perforator23, thus disabling perforator 22 and permitting perforator 23 to recorda deferred message.

Cut-olf relay 35| has its winding connected to battery 352 and alsothrough the contacts of detector relay 386 and contacts of message-endtest relay 402 to ground, forming release circuit C.|9.

OPERATION or PmroRA'roR SYSTEM Assuming that calling station has beenconnected 'to repeating relay 360 over circuit C 6, and that the firstletter o1' the address is B, the operation will be as follows:

T ime s--seleeting the performer In idle condition of waiting, the twoperforators 22 and-23 have their starting magnets 386 and 420continuously energized over circuits 'C.I0 and C.|I for the urgent anddeferred messages.

A starting impulse preceding a -code for letter B deenergizes repeatingrelay 360 and interrupts both circuits C.|0 and C.||`, deenergizing bothstart magnets 386 and 420, and releasing both brush arms 385 and 426 inboth perforators 22 and 23. The first signal of code for letter B is amarking signal which energizes repeating relay 360 and operates it toclose its contacts. At this instant the arms 385 and 426 are ine'ngagement with their No. 1 segments and circuit C.|2 is completed.

Relay 4|0, energized bycurrent in circuit C.|2, operates its armaturesto interrupt all operating circuits in perforator 23. Relay 4|0 andmagnet 31| close holding circuits C.|4 and C.|5, but the movement of thearmature of magnet 4|6 is without effect at this time.

To perforate tape 405 in accordance with^ letter B, repeating relay 360is unenergized while brush arm 385 engages its No. 2 and No. 3 segmentsbut is energized while it engages No. 1, No. 4, and No. 5 segments'forming circuits C.|2 and C.|6 and energizing magnets No. 1, No. 4, andNo. 5 of code magnets 31| and 312. No correspending circuits arecompleted inperforator 23. Each operated code magnet forms its holdingcircuit C.|4, thus registering upon the set of magnets 31| and 312 thecode for letter'B.

Brush arm 385 closes circuit C.|8 through switch 384 as traced above tooperate magnet 385. Magnet 315 operates its armature thereby perforatingtape 406 by punch pins 314 with the code of letter B and themechanism ofthe perforator steps the tape 406 into position for a succeedingperforation, as is fully described in the patent referred to. i

Brush arm 385 of perforator 22 engages segment 381 and closes circuitC.|0 to energize magnet 306 and brush arm 385 then stops in its normalposition in mechanical engagement with the short end of armature 390.Brush arm 426' in perforator 23 engages segment 42| but does not closecircuit C.|I to energize magnet 420 because common wire 422 is open inrelayl4|0. Brush arm 426 therefore stops'in mechanical engagement withthe long end of the armature of magnet 420 and remains in that positionuntil circuit C.|l is closed by deenergization of the relay 4|0 :Thiscompletes the cycle of the first letter,

leaving relay 4| 0 and magnet 4|6 energid by circuit C.|5, brush arm 426off-normal and common Wire 422 open in relay 4|0.

Time 5,--Subsequent codes except blank codel Time G-Message-end signalIn response to blank code, a starting impulse releases relay 360 whichopens circuit C.|0, and brufh arm 385 starts, engaging segments Nos. l

'to 5 successively, but contacts of relay 368 are go open for all fivesignals in "blank code and no current flows in circuit C.|2 or circuitC.|6 to, energize any magnet 31| or 312 nor is detector relay 396energized. Brush arm 385 closes circuit C.|8 to operate magnet 315 andmessage-end g5 test relay 402. The tape is then advanced one step topresent an unperforated area of tape opposite punch pins 314 and contact`of relay 402 closes message-end circuit C.|9 momentarily. Relay 35| isenergized and when operated it holds 30 its armatures two seconds aftercurrent ceases. Repeating relay 360 is maintained energized by a circuitthrough contacts of relay 35| and 'resistance 358 to ground.Communication cirnoms une l5 open from battery 331, after remy 4 332 hasreleased its top armature and until after slow-to-release relay 3|3 hasreleased its armature.

After one-quarter second from voperation of .45 vrelay 35|, relay 3|3releasesits armatures. Motor 300 vstops and an accounting device, Fig.14, operates.

After one-half second from operation of relay 35|, relay 366 releasesitsarmature, thereby restoring line I5 to normal condition of idleness.

Two seconds after operating. relay 35| releases its armatures. The upperarmature and back contact close test circuit .C.3 to render trunk I1 andits wire 322 idle-by-test.

Deenergization of relay 364 opens holding circuit C.|5 deenergizingrelay 4|0 and magnet 4|6. Deenergization of relay 4|0 connects wire 422to ground 423 and closes circuit C.|I'toenergize fmagnet 420 to permitbrush arm 426 to advance to normal position. Deenergization of magnet4|6 permits its armature and` pawl to drive ratchet 43| one step andthus separate the con-' tacts 435 and open circuit C.2| to deenergizerelay 432.

RmRANsMIssIoN APPARATUS lFor checking codes of a repeated vaddress foraccuracy a double tape-reader is provided to read' the two parts of arepeated address simultaneously and to compare the two readings (Fig.6),.u 70 A friction driven shaft 440 carries contact-operating cams'44|', 442 and a cam 443i Cam 44| operates contacts 444to-close when cam44| is off Inormal, and cam 442 operatescontacts 445 and 446 toclosewhen cam 44,42 is from v45 to 190 75 of rotation. Cam 443 operates camfollower 441 to lift it from ten bellcranks 45| operated by springs 452so that a set of five principal feelers 453 and a set of ve auxiliaryfeelers 454 coopverate with tape 406 which was previously perforated bythe mechanism 22, Fig. 5. The distance between sets of feelers is suchthat perforations for two rst letters of the repeated address may beengaged by two sets of feelers at the same time. Another shaft 455 witha feed wheel 456 steps tape 406 for each operation. When any principalfeeler 453 passes through a perforation in tape 406 it operates arocker, such as 460, against tension of its spring 46| to close a switch462, closing circuit 0.29 from battery 490 to ground, to operate one ofve'multi-contact code relays 41|, 412, 413, 414, and 415. When anyauxiliary feeler 454 passes through a perforation in tape 406 itoperates a rocker, such as 463, against tension of its spring 464 toreverse one of five switches 466, 461, 468, 469, and 410. Each of theseswitches has its two contacts connected in circuit 0.30 to be described,to contacts of a iith amature of a corresponding code relay 41| to 415.Cam contacts 444 are connected from ground through the winding' of atransmission cut-out relay 416, and through contacts and all rst andsecond armatures of all code relays 41| to 415 to'battery 490, formingcircuit 0.26, also through lower armature and y contact of relay 416 andthrough winding of magnet 505 to battery and ground, forming circuit0.25, while cam contacts 446 are connected in circuit 0.28 with contactsof a relay 411, lamp 480, winding of relay 48| and battery 482, and

vcam contacts 445 are connected in circuit 0.30,

over'wire 484, through all fifth armatures of code relays 41| to 415,and through all switches 465 to 410, through the winding of test relay485, the upper back contactV and armature of relay 416, battery 5H,winding of relay 411 and right-hand winding of magnet 483. A branch wireconnects ,wire 484 to the front contact of relay 416, forming `a shortercircuit 0.21, containing only the contacts of relay 416, battery 5H,winding of relay 411, a winding of magnet 483 and contacts 445. Shaft440 also carries stop arm 486 which is stopped at normal position by anarma.- ture of a switching start magnet 481 but is cleared when magnet4,81 is energized to attract its armature. Arm 486 may be stopped at its60 position by an armature of stopmagnet 483 but is cleared when magnet483 is energized to attract its armature. Shaft 440 advances feelers 453and 454 to test tape 406 during the first 45 of its cycle and during thelast 170 of its cycle it withdraws the feelers and operates shaft 455 tostep tape 406. j

In each code relay 41| to 415, its third armature is the messagetransmitting armature in circuit 0.31, and is connected over common wire49| `to the battery 490 and each such armature has its front contactconnected over an individual wire 492 to a corresponding segment ofdistributor 25. In each code relay, its fourth arma- `ture is theaddress-sending armature and is connected in circuit C.3 over anindividual wire 493 to a corresponding segment of the distributor 24,with back contacts of those armaturesfconnected to positive battery 494for transmitting spacing signals and with front contacts of thosearmatures connected tonegativ'e battery 495 for transmitting markingsignals. All sixth arma--I tures of the code relays 41| to 415 areconnected in mltiple'to the battery 496 and all front contacts thereofare connected through the winding of relay 491 to the battery 496,forming circuit 0.24.

Shatt 455 carries also a pinion wheel 500 with which is associated meansfor returning tape 406 after transmission of an address so that theaddress may be transmitted again. A tapereturn solenoid 50| has aninternal armature 508 to which is pivotally attached a rack 502 whichcooperates with pinion wheel 500. A striker arm 503 is xed upon thearmature 508 of magnet 50| and operates to close a switch 504.Cooperating with rack 502 is a bellcrank armature 506 operated by a.magnet 505 and a spring 501. Armature 506, rack 502, and pinion 500 areso related that the armature may depress the rack into engagement withthe pinion or may effect their disengagement, the rack may be returnedby solenoid 50| from any position to which it has been advanced, thewheel 500 may turn freely of the rack when the rack is lifted, and therack and pinion engage each other, either to operate lthe other, whenthe rack is depressed by the armature. A short forward motion of therack will engage it under a fixed detent 529 and a further movementcauses it to engage and operate armature 509 of a magnet 5|0. Thefuncvtions of the device will appear in the descripthe right-handterminal of resistance 520 and also is connected through the winding ofmagnet 5|8 andarmature and front contact of test relay 485 to theleft-hand terminal of resistance 520 and thence through contacts ofrelay 432 in message indicator 382, Fig. 5, and contacts of relay 48|,Fig. 6,: through back contact and lefthand amature of relay 522, andthrough winding of magnet 481 to battery 528 and ground 52|. Relay 48|has its armature connected also through contacts of relay 522 to batteryand ground. Circuit 0.22 extends also from brush arm 5|1 through backcontact and amature of magnet 5|0, upper winding of relay lll3, contactsof slow relay 523 and top contacts of relay 5|5 to wire 524.

Message transmitter 25, Fig. 6, comprises distributor containing fivecode segments, a normal segment 525 and an unconnectedstartingsignal'segment 525, alsoa local switch 521, a brush arm 530' forengaging the commutator segments and for closing the local switch, and astart magnet 53|. 'Ihe brush arm 530 is carried'by a shaft 532 whichcarries also a cam 533 which normally holds depressed five pivotedmembers 534, Fig. 6. In its rotation, cam 533 frees the iive members 534and permits them to` rise under tension of theirl iive springs 535 tolift feelers 453 against or through tape 485.

The magnet 53| Ais connected in circuit 0.39. fromone terminal throughcontacts of relay 523 to battery 535 and from the other terminal throughwire 660. switch 504, wire 65|,switch 401, Fig. 5, wire 652 and contactsof relay 5|5 to battery 535.

The local switch 521 is connected in circuit 0.24 in series with battery496 and the winding of relay 491 and the normal segment 525 is connectedin circuitl 0.31, from battery 496, segment 525, arm 530, and lowerwinding of relay 5|6 t0 wire 66 which extends into Fig. 7. Test relay5I5 has its upper winding connected to its top armature and backcontactin circuit 0.22 and has its lower winding in circuit 0.31 connected toits second armature `and front contact. The winding of the magnet 5|6 isconnected to the V battery 531 and to the f ront contact of the armature569 in an alternativebranch of circuit 0.22, while lower winding ofrelay 5|3 is connected from battery through contacts of relay 48| toground.

Apparatus is provided for receiving at an at- :magnet 483, and battery544.

SELECTOR APPARATUS Each selector 26 to 41 inclusive, Fig. 1, seeselector 26, Fig. '1, comprises flve'notched code bars 55|., 552, 553,554, 555 andra plurality of vdetector bars or letter bars, A, B, Y, Zand Lothers which overlie the code bars and drop intO the notches of thefive code bars when ve notches are aligned under any letter bar. Alocking bar 556 holds up all letter bars or releases all letter bars sothat one of them may drop into aligned notches in the code bars. Eachcode bar may be operated by a polar magnet either the long end or theshort end of an arma'.

556 to 566 inclusive and the locking bar 556 may be operated by a magnet56|. Each such selector has also a distributor comprising iive codesegments, 1 to 5 inclusive, with grounded seg- Vments between, aresistance segment 562 withresistance 563, holding segment 564 and anormal segment 565, also a local switch 566. A brush arm 516 engages thecommutator segments in order and also ,engages and closes switch 566.The brush arm stops by engaging mechanically ture 51| of a startingvmagnet 512. The starting magnet 512 is marginal, will not operate itarmature with a current of 30 m. a., will operate its armature with acurrent of 60 m. a., will lhold its armature with a current of 10 m. a.,and willhold its armature through apolar reversal with currents of 30 m.a. Electrical contacts 513 in the nature of relay contacts are providedfor the letter bars, each letter bar closing four pairs of suchcontacts. One contact of each such pair is connected to a common wire566, 58|, 582, or 563, common to all letter bars, and the other contactof the pair is connected to a wire of a group vindividual to theA letterbar, as 585, 586, 581, and 588. When a letter bar operates to close itscontacts, the pair of contacts of the wire 581 closes before theremainingrthre'fe pairs. An incoming signal wire 524 associated x.withtrunk wire 66 is connected through the winding of starting magnet 512 tobrush arm 516. The ve code segments of the distributor are connected bytive individual wires to the ve code magnets 556 to 566 inclusive, andthe intervening segments and normal segment 565 are connected to ground596. Segment 562 is connected through resistance 563 to ground 596.Holding segment 564 is connected to a contact of the middle armature oi'relay 59|. One contact plate o! the local switch 566 is connected toground 596, while the other plate is connected through the winding ofmagnet 56| to grounded battery, forming circuit 0.32. When brush arm 516stops in holding position, circuit 0.32 is held closed, and wire 524 isheld connected through the magnet 512 to holding segment 564 and thenceto contacts of relay 59|, resistance 594 andA ground, forming anextension for circuit 0.22.

The winding of a test relay 59| is connected from common wire 583 toground through resistance 592 and through wire 583, letter-barcontacts-as 513, wire 586, brush 668 in switch 666, wire 6|3, relay 6|4and battery 634, forming circuit 0.34. 'I'he top armature and frontcontact of relay 59| are connected to resistance 592 and to ground, themiddle armature is connected through the winding of relay 593 to comtobrush 666 in switch 666, and the bottom armature and back contact areconnected to ground and to common wire 582 and through contacts as 513and winding of magnet 661 to battery, forming circuit 0.33. The armatureand front contact of relay 593 are connected to common wire 566 and toincoming trunk wire 66, to extend circuit C. 31.

Each group 'of letter-bar wires, as 585 to 588, extends to arotarysearching switch 666 of which there may be one for each letterbar. Each switch 666 comprises a set of rotary brushes, a fleld of tlxedcontacts for the brushes, and an electro-magnetically controlled powermeans for driving the brushes. A continuously driven power drum 66| islocated near a brush drum 662 xed,

on a brush shaft 663 vwhich carries three brushes, a brush 665 connectedto wire 565, a brush 666 connected to wire 586,and a brush 666 connectedto wire 566. A clutch magnet 661 has an armature and crank arm 6|6 withan idler friction wheel 6I I. When magnet 661 attracts its armature 6| 6the wheel 6|| is moved to engage both drums 66| and 662 thus drivingbrush shaft 663 and the three brushes.

The trunks among which the switch 666 searches comprise each threewires, a communi' cation trunk wire, as 68 connecting switch 666 toselector 34, an accompanying signal wire as 6|2 corresponding in thesecond selector to wire 524 in the iirst selector, and a local busy testwire 6|3 connecting switch 666 to the test-control relay 6I4 the sameas-relay 356 of circuity 0.3 inFlg. 5.

THE FINAL SELECTOR A nal selector 56, Fig. 10, is mechanically similarto selector 26 except that the letter bars close only three pairs ofcontacts, there is no 'searching switch, and the relay arrangement isFig. 4

-mon wire 58|, and through letter-bar contacts Ormarron or Smcroas Theoperation of the selectors is started by deenergization of relay 432 inmessage indicator 382, Fig. 5, which occurs when the message-end signalof blank code is received by perforator 22. The armature and backcontact of relay 432 close the switch starting circuit 0.22, extendingas described, from ground 52|, Fig. 6, to wire 524 and now to magnet512, Fig. 7, of first selector 26, brush arm 510, normal segment 565, toground at 580. When this circuit is completed, magnet 481 is operatedand the operation of its armature releases arm 488 and friction-drivenshaft 440 starts. 0am 44| closes the contacts 444 to form circuits 0.25and 0.26, as traced above.

During idleness, the holding circuit 0.23 has held energized thesolenoid 50|, Fig. 6. Current in circuit 0.22 now energizes and operatesrelay 5|3 to open the holding circuit and to deenergize the solenoid50|.

Also during the period of idleness the holding circuit 0.24 is heldclosed by local switch 521 in distributor 25 thus holding relay 491energized and holding its contacts open to maintain relay 523unenergized. I'hese conditions now continue.

Time 7--Blank-tape clearing In 'the condition of idleness which precededthe seizing of trunk I1 by substation l0, tape 406 `was blank,containing feed perforations but no code perforations, from perforatorpunches 314 to feelers 453. This distance is but a few inches but codeperforations of the received message now are preceded in tape 406 bytape which is blank other than for feed perforations. Feelers 453therefore have been released by cam 443 but have not risen through tape406 because of the absence of any code perforations. The tape 406therefore tests blank to feelers 453 and circuit C.26 as traced abovemay be formed, which energizes relay 416 and opens circuit 0.25.

Cam 442 closes contacts 445 and forms the transmission cut-out circuit0.21, energizing magnet 483 to permit arm 486 to pass without energizingmagnet 5|8 for transmission. Cam 442 also closes contacts 446 to formcircuit 0.28 to energize lamp 480 but current in circuit 0.21 energizesrelay 411 to open circuit 0.28 so that lamp 460 does not glow.

Circuit 0.22 holds magnet 481 energized and circuits 0.26 and 0.21 arecompleted at each rotation of shaft 440, until all blanks in the tape aswell as letters" or "unshift" codes have been fed past feelers 453 andcode holes are encountered by those feelers.

Time 8-Operatz'on of the first selector 'I'he first letter of theaddress of the message reaches principal feelers 463 and the same letterrepeated reaches auxiliary feelers 454. Circuit 0.22 remains closed andmagnet 481 remains operated to pass arm 486v without a pause. Tape 406is perforated as shown in Fig. 2. The two sets of feelers 453 and 454respectively are separated by a distance equal to six steps of tape 406so that when flrst letter B of the address of the message is in positionto be read by feelers 453, second letter B of the address of the messageis in position to be read by feelers 454 as a check upon the accuracy'of the address codes.

Shaft 440 rotates and approaches the armature of magnet 483. 0am 443permits a set of ve feelers 453 and a set of auxiliary -feelers 454 torise to test the tape for code combinations of perforations. feelers 453and the first, fourth, and fifth feelers 454 pass through tape 406 andclose their associated lower contacts. Relays 41|, 414, and 415 areenergized over their three circuits 0.29 in accordance with the code forletter B.

Cam 44| closes contacts 444 to form circuit 0.25 and magnet 505 isenergized. Circuit 0.26 is not formed because at least one code relay isenergized. Cam 442 closes contacts 445 to form circuit 0.30, tracedabove. Relays 485 and 411 and magnet 483 are energized. Relay 411 opensthe lamp circuit. Test relay 485 substitutes magnet 5|8 for theresistance 520 in circuit 0.22, thus reducing the total resistance ofthis circuit and increasing the current in the circuit to m. a.,operating the magnets 5|8 and 512. Magnet 48,3 attracts its armature andclears the path for arm 486.

The speed of brush arm 5I1 is double that of arm 486. Therefore, whileshaft 440 rotates from its 45 position to its 190 position the brush arm5|1 will reach position 290 on segment 5|6. The distributor arms 5|1 and510 however move in unison and are released upon the energization oftheir start magnets.

When brush arm 5|1 leaves normal segment 5| 6, circuit 0.22 isinterrupted and magnet 481 is deenergized. Address signal transmissioncircuit 0.3| as traced above then is effective ve times, for eachmarking signal through negative battery 495, and Afor each spacingsignal, through positive battery 494. The magnets 556 to 560 are thusenergized in polar manner and in a code combination.

The code for B now has been set on first selector 26. When brush arms5|1 and 510 reach the position of 290, the arm 486 is at 190. Contacts445 are opened, thereby interrupting circuit 0.30 and deenergizing relay485. Arms 5|1 and 510 interrupt circuit 0.3| by leaving their No. 5segments andform circuit 0.22 by engaging their segments 5|6 and 562respectively.

, At this time circuit 0.22 extends from ground 52|, through battery528, Fig. 6, through unenergized magnet 481 and resistance 520, segment5|6, brush arm 5|1 in motion, upper winding 1 of relay 5|3, wire 524,energized magnet 512, Fig. 7, brush arm 510 in motion, segment 562,resistance 563, to ground at 590, with a currnet of l0 m. a. flowingtherethrough. Brush arm 518 in selector 26 engages mechanically the longend of the armature of magnet 512 and stops at its 315 position. thusswitching circuit 0.22 from segment 562 to holding segment 564 whencethis circuit extends through contacts of the middle armature of relay55| and resistance 584 to ground. 'I'he current remains 10 m. a. becauseof the resistance 534, substituted for resistance 563. but brush arm 5|1stops at its normal position without changing the circuit. Mag-` net 481now has 10 m. a. which is not sumcient toY- operate its armature andrelay 5|! has 10 m. a. and holds its armature as does magnet 512.

At the time of engaging segment 562, brush arm 510 also closed localswitch 566 and therefore closed circuit 0.32, causing the energizationof magnet 56|. Locking bar 550 is consequently operated and mechanicallyunlocks all bars of the set of letter bars having code relation with thecode bars 55|.to 655. 'The code relation is such that when thepredetermined code, as B.

The first, fourth, and fifth' Cil is set upon the code bars 55| to lll,the' letter l bar B will be unrestrained by any bar 55| to 585 and allother letter bars will be restrained from movement to close theirelectrical contacts. As

now described, code bars 55| to 555 are set for 'switch 888 byconnecting them to the individual Wires 585, 588, 581, 588, which startsto rotate when the iirst contact is completed to establish circuit 0.33.

Searching switch 888 now is rotating and letter bar B closes allcontacts, closing the testing circuit 0.34. 'I'he action in the circuit0.34 is identical with the action in the testing circuit 0.3. Busytrunks give to the brush 888 a current insulcient to operate the testrelay 58|, while an idle trunk gives current suilicient to operaterelays 58| and 8|4. Should two relays as 58| Atest the same trunk wireas 8|3 at the same time, the relay 8|4 would operate and the searchingrelays would not operate. reject the trunk as busy and both searchingswitches would continue to rotate. When an idle trunk has been found,relay 59| operates its top armature to shunt the resistanceI 592 andrelay 8| 4 is energized to render the wire 8|3 busyby-test. Relay 58|operates its bottom armature to open ythe drive circuit 0.33 and thefinder 'switch 888'stops in engagement with the tested and seized trunk88. Relay 58| also operates its' middle armature to switch circuit 0.22from the vresistance 584 and to extend this circuit from the holdingsegment 584 through the middle armature and front contact of relay 58|through winding of relay 593, contacts of letter bar B, brush 888 andcontact in switch 888, wire` 8|2 to selector 34, magnet, distributorarm' and normal segnrent to ground 835.

When the circuit just traced is established, relay 583 operates andconnects wire 88 to wire 588 and thence to wire 585 thus effecting theflrst step in building up the message transmission circuit 0.31 to bedescribed.

The current now ilowihg in circuit 0.22 and its ilrst extension to theseco'nd selector, increased by removing the resistance 594, isapproximately 30 m. a. which energizes switch starting magnet 481 tooperate its armature for the second letterof the address, to beregistered upon the second selector 84. K At the instantwhen relays 58|and 8|4 operate, arm 485 is approaching the armature of magnet 481 ifthe search of switch 888 has been' short, as is in mechanical engagementwith the armature of magnet 481 if the search of switch 888 has beenlong. During the period of the last i of shaft 448, feelers 453 and 454have been withdrawn from tape 488, then shaft 455 has Both searchingrelays would l 1 1v Time s-B-nefective address A message having adefective address, or in which the code address has not been repeated;will be sent to an attendants desk and the attendant then will corrector complete the address and will forward it by the automatic selectingand transmitting devices. y l

Should any letter of the address not correspond to its companion letter,test circuit l"0.38 will not be formed between code switches Y486 to 418and correspondingcode relays 41| 1:60415.

` Stop magnet 483 is not charged by circuit'j`0.38

and arm 488 stops at 60 in mechanical engage'- ment with the armature ofmagnet 483. 0am contacts 448 close lamp circuit 0.28, -rely'41fl is not'energized by circuit 0.38 and'lamp488 lglows to signal the attendant.Relay 48| i-'ffen'ergized by current in circuit.C.28, opens circuit`022,de energizing magnet 512 in all selecto storing all selectors, anddeenergizi'ng ela thus energizing solenoid 58| to ret to its startingposition. il*

The attendant noting the signal,.;1nserts plug' 54| into jack 542. Jackcontacts l 543vzlose a circuit including battery 544, lef handf-iwindingof magnet 483 and the winding f' lay""522. which causes magnet 483 tattra'c't its ar and permit arm 488 to start yfro v The left-handarmature and? v relay 522 open the windin 'f`UI selector 28 with acurrent 'f 38 not operate magnet-512 the? selector Switch 548 isnormally ope" -Aft'er inserting the plug 54| and when thevlainp unibasbeen' extinguished the attendant closesvthevswitch 546. 40 thus forminga branch vof circuit 0.31 from wire 88 to ground. "u 498, over commoncontacts5'84 and thus fclses lie* cont-rol ciici 0.38 describ'ater...shereiriftherby energizing the starting gnetl53li off th'idit'ibtthe distributom25 ftra'rsihit the :e to the receiver:5.48.@.1`Shouldithe fzaddressee.. n the oper` at the. iginatingmsubstation beenturnedv` to advance tape 488 and rack 582v L M f ti one step. Return offeelers |53 has opened switches 482 to deenergize all relays 41| to 4:15thus forming circuit 0.28 to energize relay '418 which opens circuit0.25 and deenergizes m 585, but the slow-to-release armature of m 585holds rack 582 in engagement with,.' 588 long enough to permit wheel5.88 to a rack and to engage the end of the raclkY 488 to present thenext two sets otcod perforations to the two sets of feelers 453 and 454.

address letter are repeated for the second address letter and forsecondselector 34. Feel- 75.

tens

